Circuit-separating device



Oct. 10, 1961 G. R. FORRER CIRCUIT-SEPARATING DEVICE Filed June 10, 1959 Unitedg States Patent Oce 3,004,120 Patented Oct. 10, 1961 3,004,120 CIRCUIT-SEPARATING DEVICE Gordon R. Foi-rer, 39710 Haggerty Court, Northville, Mich.

Filed June 10, 1959, Ser. No. 819,468 10 Claims. (Cl. 200-61.08)

This invention relates to electrical circuit connection devices and, in particular, to devices for the connection of a second load circuit in the event that a first load circuit becomes inoperative or otherwise undesirable for further use.

One object of this invention is to provide a circuitseparating device with a breakaway electrical contact device adapted normally to maintain an electrical connec-A tion with a first electrical load circuit but which, by breaking away a portion thereof, immediately disconnects the first load circuit and enables the connection of a second load circuit without substantial interruption of service dependent upon a load circuit. l v

Another object is to provide a circuit-separating device with a breakaway electrical contact device of the foregoing character having a second load circuit contact adapted to energize the second load circuit but temporarily prevented from doing so by the presence of a first load contact superimposed upon the second load contact in spaced or otherwise insulated relationship therewith and shielding the second load contact from engagement with an electrical current supply contact.

Another object is to provide a circuit-Separating device with a breakaway electrical contact device as set `forth in the object immediately preceding, wherein the base portion at a weakened junction permitting easysev-y erence of the contact portion from the base portion so as to expose the second load contact `for further use.r

Another object is to provide a circuit-separating device with a breakaway electrical contact device of the foregoing character wherein the first load contact is in the form of a cap joined to its base portion by a breakable neck portion enabling the cap to be lifted and broken oft when it is desired to discontinue operation of the rst load circuit and initiate operation of the second load circuit.

Another object is to provide a circuit-separating device with a breakaway electrical contact device of the foregoing character which can be used to separate a reg` ular or main electric working circuit froml an emergency or standby circuit, so as to enable the standby circuit to be in constant readiness for use when for any reason the further operation of fthe main circuit becomes undesirable or infeasible, for example, to provide a safety circuit alongside an operating circuit, or in mining or other operations t provide a test circuit alongside a safety circuit, or toy provide an emergency alarm circuit beside the main circuit or, as in rocketry, to provide a test circuit wherein no danger exists of energizing the firing circuit until the emergency or safety contact is exposed by breaking ol or breaking away the main contact,

thereby also preventing the main circuit from being re-y established. t

Other objects and Ladvantages of theinvention will become apparent during the course of the following description of the accompanying drawings, wherein:

FIGURE \l is a diagrammatic View of a circuit-separating device for a dually-operative electricalv system containing two separate load circuits adapted to be connected sequentially to an electrical supply source by a breakaway contact device shown in central vertical section, ac-

cut in the second load circuit and cut out the first load circuit;

FlGUREB is an enlarged perspective view of the breakaway main contact device in its normal operating position, with the contact cap in the position of being broken away from its base portion in dotted lines; and

FIGURE 4 is a diagrammatic View of a modification of the invention using a screw-type appliance in a screw socket, the appliance being partly unscrewed from its socket to show its construction more clearly and having two load circuits and incorporating the breakaway contact device of the present invention for separating them from one another.

Referring to the drawing in detail, -FlGURE :l shows a dually-operative electrical system, generally designated 10, including a source of electricity 12, such as a storage battery, current supply main or the like, rst and second load circuits 14 and 16 with first and second electrical load units 18 and 20 respectively connected therein through the action of an electrical circuit-separating device, generally designated 22. 'The circuit-separating device 2-2 includes an electrical supply contact 24 engaging a breakaway contact device, generally designated 26, according to the present invention. Thesupply contact 24 forms a part of the current supply connection, generally designated 25', which includes a movable spring abutment 27 and spring 29 engaging the contact 24. The supply connection 2S is movably and mechanically connected through'the spring abutment 27 to the remainder of the circuit-separating device 22. The supply contact 24 is connected by the line 28 to the electricity source l2 from which the line 30 runs to both of the load circuits 14 and 16 to energize one pole 32 ork 34 of each of the load units 18 and 2t).k The vopposite poles 36 and 38 are connected by lines'4il and 42 to marginal and central screws 44 and 46 respectively, one of the screws 44 and the screw 46 forming electrical connection terminals of the circuit-separating device 22.

The circuit-separating device 22 is mounted ony a base plate 48 of insulating material having a central boss 50 therein provided with a central bore S2 and counterbore 54. The base plate 48 is also drilled yat equal radial distances from the bore 52 with holes S6 for receiving the marginal screws 44, one of which is the marginal terminal. The central terminal screw 46 is threaded rinto the lower end of the shank of a central contact or second load contact 58 located immediately below and in line with the electric supply contact 24. The supply contact 24 is normally prevented from engaging the second loady contact 58 by a shielding action effected by the breakaway contact device 26 previously mentioned and shown, apart from its other connections, in FIGURE 3.

The breakaway contact device 26 consists of a base ring 64 (FIGURE 3) which is drilled with holes 66 at circumferentially-spaced intervals in alignment with the ybase plate holes 56 to receive the marginal screws 44 which secure it to the base plate 48. The breakaway contact device 26 is, of course,.of electrically-conducting material, such asmetal, and has an opstanding neck portion `68 terminating at its upper end in a removable first load contact or cap 70 preferably of arch-shaped ory dome-shaped form arching over the second load contacty 58 in vertically-spaced relationship and shielding it from engagement by the supply contact 24. The cap 70 has a stop tab 72 extending downwardly from the edge 73 at a location diametrically opposite the neck portion 68. The latter is rpreferably provided with an indentation or other weakening depression or perforation 74 so as to kfacilitate 3 breaking off and removal of the cap 70 as described below in connection with the operation of the invention. As will be seenfromFIGURE 1, the electrical `supply contact 24 is maintained normally in contacting engagement with the cap or tirst load contact 7 0 by the spring 29. The base ring 64 has circumferentially-spaced downwardly-bent integral prongs 76 which are embedded in the base plate 48 to prevent shifting of the base ring 64.

In the operation of the invention shown in FIGURES l to 3 inclusive, let it be assumed that the parts are in the positions shown in FIGURE 1, with the electrical supply contact 24 engaging the central cap or iirst load contact 7i) as a result of the pressure of the coil spring 29, and that the electrical connections have been made in the manner shown. It will be understood, of course, that the lines 28 and 30 connected to the electricity supply source 12 energize the supply contact 24 and poles 32 and 34 respectively of the iirst l`and second load units 18 and 20. The latter may consist of any type of electrical equipment imposing an electrical load, such as electric motors, electronic tubes or tube circuits, heaters or other resistors, solenoids or other magnets, electric light bul-bs or other illuminating devices, and so forth, It will be assumed that each of vthe load units 18 and 20 has its own switch (not shown) whereby it can be thrown into or out of circuit with the remainder of the rst and second load circuits 14 and 16, the load units 18 and 20| being shown constantly in circuit =for simplicity of illustration. v

Under the circumstances shown in FIGURE l, electric current from the source 12 flows through the line 31) to the poles 32 and 34 of the iirst and second load units 18 and 2t) but the pole 38 and line 42 of the second Iload unit 2t) remains temporarily unenergized because of the spacing of the second load contact 58 away 'from the electrical supply contact 24 by the cap 76; The first load unit 18, however, is immediately energized by current flowing therethrough from the pole 32 to the pole 36, thence by way of the line 40, screw 44, base ring 64, neck portion 68 or tab 72 and cap 70 of the breakaway contact device 26, to the supply contact 24, completing the circuit.

If, now, the iirst load unit 18 becomes inoperative or for some other reason it is desired to discontinue its operation, the operator shifts the supply connection 2S relatively to the base plate 48 and breakaway contact device 26 by swinging it upward around a pivot connection (not shown) with the base plate 4S, so as to provide room for removing the cap 70. The operator now pries the cap '76 upward into the dotted line position shown in FIGURE 3, yas by inserting a screw driver under the edge 73 thereof. Alternatively, the operator, by means of a pair of pliers, can grasp the portion of the cap 79 adjacent its edge 73 and swing the cap 70 upward, moving it back and forth vertically until the metal at the weakened recess 74 of the neck portion 68 fractures, detaching the cap 70 lfrom the base ring 64. The circuit-separating device 22 now has the appearance shown in FIGURE 2, with only the base ring 64 and part of the neck portion 68 remaining. TheV operator then moves the current supply connection 25 downward so that the supply contact 24 thereof now directly engagesthe second load contact 58, whereuponthe operator again closes the line switch. The central contact or second load contact 58 is now energized from the electricity source 12 through the line 3l), the now closed switch, the pole 34,V the second load unit 20', the pole 38, line 42, second load contact 58, supply contact 24 and line 28'back to the electricity source 12, completing the circuit. The second load circuit 16 is now energized and the first load circuitv 14 is de-energized and henceforth not only isolated from the second load circuit 16 but prevented from -further renergization,

TheV modified electric circuit-separatingYV device, generally designated S0, shown in FIGURE 4 has the same general purpose as the circuit-separating device 22 of FIGURES 1 and 2, but is dierently constructed. It is, however, connected to electric current supply lines 82 and 84 on the one side and by .a line ,86, on its opposite side to first and second load circuits 88 and 90, thereby energizing the poles 91 and 93 of the rst and second load units 92 and 94. The remaining or opposite poles 96 and 98 are connected by the lines 100 Iand 102 to the iirst and second contacts 184 and 106 of the breakway electrical Contact device, generally designated 108, at the locations 109 and 111,1. The breakaway electrical contact device 108 is embeddet in the center of the frustoconical end member 110 of the base 113 of an electrical lappliance, generally designated 112 having, as here shown, a metallic screw-threaded side portion 114 to which the line 86 is connected as at 115. The appliance base 113 may, for example, be the base of a so-called Edison-type incandescent light Ibulbof which the load units 92 vand 94 may consist of dual ybut independent iilaments.

The screw-threaded side portion 114 is threadedV into the correspondingly threaded bore 116 of an internallythreaded metal sleeve 118- which forms the inner part of a socket, generally designated 120. rEhe cup-shaped outer part 122 of the socket 126 is of insulating material, such as plastic and has a cylindrical side wall 124 in which the internally-threaded sleeve 118 is embedded, `and also has an end wall 126 immediately behind a recess 128. Embedded in and extending through the end wall 126 is a metallic electrical supply contact 130 to which the supply lineY 82 is connected, as at 132. The supply line 84, on the other hand, is connected as at 134 to the internally-threaded sleeve 118, the threaded bore 116 of which is frictionally engaged by the externallythreadedA side portion 114 to establish electric contact therebetween.

The outer or rirst load contact 1414 of the breakaway electrical cont-act device 108 consists of a supporting member or stem 136 embedded in the end member 110 to one side of the center thereof. The stern 136 joins the contact cap 138 at a weakening notch or recess 140 placed close to the top ofthe end member 110 to minimize the height of the remainder of the stem 136 when Ibroken off. The cap 138 is of approximately C-shaped cross-section and arches over the second load contact 106 with `an insulating button 141 disposed therebetween to prevent the cap 138 from being pushed into contact with the second load contact 106 as well as to shield the latter from contact with the electrical supply contact 130. While a screw-type or so-called Edison-type base and socket are shown in FIGURE 4, it will be understood that the invention may optionally employ the well-known bayonet, Ediswan or other conventional base and socket.

In Ithe operation of thepmodified electrica-l circuit separating device 811, assuming that the electric current supply lines 82 and 84 are energized, when the base 113 of the electrical appliance 112 is screwed completely into the threaded bore 116 of its socket 120, the cap 138 of the lirst load contact 104 engages the supply contact 130 and thus closes the circuit to the first load unit 92 by way of the threaded sleeve 118 and threaded side wall 114, and lines 86 and 100. t

If, now, the kfirst load unit 92 becomes inoperative or yfor some other reason isY to be placed out of operation, the operator unscrews the base 113 of the appliance 112 from the socket so as to completely remove it and expose the break-away electrical Contact device 108. With a pair of pliers or a` screw driver he pulls upward or pries upwardon the c apV 138,7pivoting it around the weakening notch14tl andswing'ingit back and forth until" breakage occurs. With-the cap 138 thus removed, the operator screws the base `113 of the appliance 112 back `into the socket 120 until the second load contact 166 engages the current supply contact 130, whereupon n) the second load unit 94 in the second load circuit 90 becomes energized through the lines 36 and 162 and the first loadunit 92 of the iirst load circuit S8 becomes iso` lated by the disconnection of the stein l yfrom any portion of the supply circuit.

It will be evident that the invention may also be applied to the end cap of the gun of a television picture tube equipped with duplicate internal circuits so that failure of one can be instantly overcome by switching in the other after removing the breakway cap, as described above.

In the circuit-separating device 22 of FIGURES l, 2 and 3, the weakening notch 74 is shown as spaced above the base ring dt, leaving the portion 68 projecting above the base ring 64 when the cap 70 has been broken oil. In actual practice, however, the notch 74 is placed close to the base ring d4 in order to reduce the height of the residual portion 68 to a minimum.

What I claim is:

l. An electrical circuit-separating device for selectively energizing irst and second load circuits, said device cornprising a supporting structurerhaving an electrical supply contact thereon, a detachable iirst load contact engageable with said supply contact and ladapted to be electrically connected to the irst load circuit, and a second load contact disposed on the opposite side of the first load contact from the supply contact in insulated relationship with the irst load contact and supply contact and adapted to be electrically connected to the second load circuit, said rst load contact initially engaging said supply contact while shielding said second load Contact from engagement by said supply contact, said supply contact being engageable with said second load contact in response to removal of said first load contact.

2. An electrical circuit-separating device, according to claim 1, wherein the flrst load contact has a supporting member mounted on said supporting structure.

f3. An electrical circuit-separating device, according to claim 2, wherein said supporting member has a weakened portion adjacent its junction with said first load contact.

4. An electrical circtut-separating device, according to claim 2, wherein the first load contact is arch-shaped and engages the supporting structure on the opposite side thereof from the supporting member.

5. An electrical circuit-separating device, according to clairn wherein the supporting member includes a base portion secured to Said supporting structure and an upstanding portion secured to said iirst lo-ad contact.

6. An electrical circuitseparating device, according to claim 5, wherein the base portion comprises an arcuate member at least partially encircling said second load contact in spaced relationship therewith.

7. yAn electrical circuit-separating device, according to claim 2, wherein the first load contact is arch-shaped and has the supporting member connected thereto on one edge portion and also has a spacing projection on a remote edge portion, said projection extending into engagement with the supporting structure.

8. An electrical circuit-separating device, according to claim 7, wherein the supporting member has a weakened portion near its junction with said first load contact.

9. An electrical circuit-separating device, according to f claim l, wherein said device includes a socket containing said supply contact and adapted to removably receive said supporting structure, and wherein said first and second load contacts are mounted on said suporting structure within said socket.

10. An electrical circuit-separating device, according to claim 9, wherein said supporting structure forms the base of an electrical appliance electrically connected to the first and second load circuits.

References Cited in the iile of this patent UNITED STATES PATENTS 2,155,789 Ganz et a1 Apr'. 25, `1939 

